The present invention relates to a cast piece subjected to bending forces comprising a casting and a core element cast in this casting.
Though a workpiece or the like, which is composed of several components, is more costly in manufacture, it affords on the other hand the possibility of reducing the weight by an optimal shaping of the workpiece. As a result, a better exploitation of material may be attained with the bending load and the mounting space predetermined. The employment of such workpieces is particularly favorable in the case of automotive vehicles, since it is more and more desirable to build a vehicle of light weight.
With respect to a known workpiece of the type referred to hereinabove, such as disclosed in German Pat. No. 2,533,058, a tie anchor having a high coefficient of elasticity and constructed as a core element is embedded in the tension area. The tie anchor being completely enclosed by the cast material is protected against high tension forces to which it is susceptible. However, since the amount of bending tension increases with growing distance from the neutral axis, an optimal exploitation of the material is not possible because the point subject to the highest tensile stress is not represented by the tie anchor but by a casting layer.
It is further known that cavities are cast in support members subjected to bending forces in the area of the neutral axis which cavities, admittedly, reduce the weight, but influence the curve of tension via the remaining cross-section. There may occur high tension at the wall surfaces close to the cavity resulting in a premature fatigue of the material in this area. In the event of comparatively small cross sections, in which case the formation of a cavity would still be worthwhile for the purpose of weight reduction, the amount of tension in the thin walls may then exceed the nominal value allowed.